Generic ground milling machines such as road milling machines, recyclers, stabilizers or surface miners are usually used in road or roadway construction or in the extraction of natural resources located near the surface. They regularly comprise a machine frame with travelling means such as wheels or crawler tracks and an operator platform. The working device of a ground milling machine usually includes a milling drum rotatably mounted in a milling drum box and equipped with a plurality of tool devices on its outside jacket surface. A drive motor, usually a diesel engine, drives the ground milling machine, in particular the crawler tracks and the milling drum. During working operation of the ground milling machine, the tool devices of the milling drum are driven into the ground and mill the ground due to its rotation about a horizontal rotation axis. The loosened milled material is conveyed onto a transport vehicle by a conveyor device, which typically comprises a discharge belt and in some ground milling machines also an input belt, and is then transported away by said vehicle. Said discharge belt is frequently a suspension conveyor. Thus, the transport vehicle and the ground milling machine together frequently form a work train, which in most cases consists of a ground milling machine and a transport vehicle travelling either ahead of or behind the ground milling machine, depending on the direction in which the milled material is transported by the ground milling machine for transfer to the transport vehicle. During operation, the ground milling machine moves in its working direction removing ground material along a milling track.
Usually, the amount of milled material is considered as a basis for calculating the remuneration for milling work. Therefore, there is an increased interest in being able to determine the amount of milled material as precisely and reliably as possible. The amount of removed ground material, for example, from roads to be renewed, soil or rock formations, is significantly determined by the length and width of the milling track, the milling depth in which ground material is removed, as well as the properties of the removed ground material per se, such as its density. One possible approach for determining the amount of milled material is thus based on a calculation using the dimensions of the resulting milling bed as described in DE 10 2011 113 752 A1 of the same applicant. However, especially in the case of ground material being composed of materials having various densities, said essentially volumetric determination often leads to a deviation between the calculated mass and the actual mass of milled material. Another option consists in using belt weighers on the conveyors of the ground milling machines as described in U.S. Pat. No. 7,470,082 B2 for a recycler. However, belt weighers have proven to be very inaccurate, particularly when being used on discharge belts, and thus unsuitable for a proper calculation of the milled material, so that there is a demand for reliable alternatives.
In order that the milling work is most cost-effective, it is furthermore important that the transport vehicles for transporting the milled material away are filled up to their maximum capacity if possible in order to prevent unnecessary additional runs. At the same time, the maximum capacity of the individual transport vehicles should not be exceeded in order to not infringe safety regulations on the one hand and to prevent damage to the transport vehicles on the other hand. It is thus also in this regard desirable to achieve a most accurate determination of the mass of the conveyed milled material.